Public opinion polls on same-sex marriage

What were the chances of a state's citizen initiative
on
same-sex marriage (SSM) passing in 2012-NOV?

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What would be the chances a state's citizen initiative passing to restore or deny SSM in 2012-NOV?

As of mid-2011, there had allegedly been 34 plebescites, referendums, amendments to state constitutions, ballot initiatives, and other citizen or legislative initiatives in the past that allowed voters to decide whether to limit or deny access by loving, committed couples to same-sex marriage (SSM). In all but one case, the voters responded negatively to marriage equality. The exception was Arizona Proposition 107 in 2006. 1 It would have reinforced the existing state marriage law that defines marriage as a union of one man and one woman. It failed by a vote of 48.2% in favor and 51.8% opposed. 2 Apparently, voters were unwilling to write discrimination into their state constitution for the first time in history.

The National Organization for Marriage, Family Research Council, Roman Catholic Church, and other conservative groups are committed to preventing SSM from spreading. They generally promote what we refer to as the "static model" of citizen initiatives. They often claim that all of the previous 30 or 31 citizen initiatives on SSM have ended up rejecting marriage equality. They seem to sincerely believe that there is no sustained increase in support for marriage equality during the past two decades. Thus, they expect that all future citizen initiatives will reject SSM as well.

On 2011-JUN-29, Nate Silver published his estimates of "projected vote share for same-sex marriage bans, November 2012." 6 He is a statistician and the webmaster of the FiveThirtyEight blog on the New York Times web site. The name of his blog is derived from the total number of votes in the Electoral College -- the group who elects the U.S. president every four years.

Silver estimated the percentage of the voters who would vote in favor of a hypothetical plebiscite that banned SSM in their state if it were held on election day in 2012. Presumably, the same value would apply to the percentage of voters who would against a plebiscite that legalized SSM. He performed the calculation for each of the 50 states and the District of Columbia using two statistical models:

The linear model assumes that support for same-sex marriage will continue to increase at about the same rate in the future as it has in the past -- an average of about 10 to 20 percentage points per decade depending upon the state.

The accellerated model incorporates trend data from national polls on same-sex marriage. He has noted that same-sex marriage appears to have gained support at a faster rate in recent years. This model will predict a lower vote share for the anti-SSM voters than does the linear model.

Using the two models, he predicts that if a hypothetical proposition like Proposition 8 in 2008 re-appeared on the California 2012 ballot, it would receive between 41.8% and 45.8% support, depending upon the statistical model used. The Proposition would thus be favored to fail. This prediction appears to have been accurate because as of the end of 2012, public support for SSM exceeded 60%. However, no Proposition was voted upon at that time. Those promoting SSM in Canifornia had abandoned the referendum approach and were pursuing marriage equality through the courts.

He also estimates that those voting against SSM in the proposed 2012 referendum in Maine to restore SSM in that state would receive between 39.6% and 43.9% of the total vote. It would be favored to win or be very likely to pass, depending on the model used. This was an accurate prediction because the voters of Maine actually did vote on SSM and passed the referendum by a margin of about 5 percentage points. Same-sex couples are now routinely marrying in the state.

A measure to amend the state Constitution in Minnesota to ban SSM was held on the 2012 ballot. Here, the linear model predicts 54.1% anti-SSM vote which would comfortably pass the measure and write gender discrimination into the state Constitution. However, the accelerated model predicts a 49.3% anti-SSM vote which would cause the measure to narrowly fail. The voters of Minnesota actually did vote on a SSM constititutional amendment. The measure failed by a margin of about 5 percentage points.

Recent developments:

With:

A federal District Court ruling that Prop. 8 is unconstitutional, and

A three judge panel of the 9th U.S. Court of Appeals confirming this decision, and

A second confirmation by the full Court of Appeals, and

The U.S. Supreme Court accepting the case in 2012-DEC,

interest in a 2012 citizen initiative to resinstate SSM has at least temporarily evaporated.

A Field Poll conducted during 2012-FEB found that registered voters in California favored marriage equality by 59% to 34%. With a 25 percentage point margin, a new proposition to restore same-sex marriages would have certainly passed on election day in 2012-NOV.

The Field Poll was replicated in 2013-FEB. It found that support for SSM is continuing to increase. The pollsters reported:

It is worthwhile noting that in 1977, the same polling agency found that only 28% of voters approved of SSM while 58% disapproved.

Percent voter opposition to SSM in hypothetical referendums held during 2012-NOV, by state:

Nate Silver predicts that opposition to SSM in a hypothetical state referendum would range from about 29.5% in the District of Columbia to about 76% in Mississippi. Of course neither the District of Columbia nor Mississippi. nor most of the other states will actually hold referendum at that time.

His predictions at the end of 2011-JUN for a hypothetical anti-SSM plebiscite in the District of Columbia and the 50 states were:

Very likely rejected with less than 40% "anti-SSM" vote: DC, VT, MA. All three jurisdictions have already legalized SSM.

Either favored to be rejected or very likely rejected (depending on the model used) with less than 50% "anti-SSM" vote : NH*, ME*.

* Four referendums were actually held on election day 2012-NOV in these states. Three of them, in Maine, New Hampshire, and Washington State legalized SSM. One, in Minnesota, failed to pass a constitutional amendment banning SSM.

Detailed information can be obtained on his blog. 1

Full disclosure by the author:

I am a supporter of same-sex marriage. But I try to remain objective when reporting on the topic and attempt to be fair to both sides. It is difficult. For the life of me, I cannot understand how basic human rights, including the right to marry the person that you love and to whom you are committed, can be approved or vetoed by a simple majority vote.

Marriage has been redefined four times in the U.S:

The first ocurred in the 1860s at the end of the Civil War. At that time, slavery ended and all African American adults became able to marry -- but only to persons of the same race and opposite gender.

The second ocurred in the early 20th century when laws in some states that prohibited deaf people from marrying were repealed.

The third ocurred during 1967 when a simple majority of the Justices of the U.S. Supreme Court voted in an ironically named lawsuit "Loving v. Virginia." Their ruling allowed interracial couples to marry anywhere in the U.S. Again, they had to be of opposite genders.

The fourth first ocurred in 2003 when a majority of judges in the Massachusetts Supreme Judicial Court ordered the state to issue marriage licenses to same-sex couples. During the next decade, the District of Columbia and eight additional states have legalized SSM as a result of legislative bills, court rulings, or citizen initiatives.

This last category of adult couples who are generally not allowed to marry in the U.S. -- same-sex couples -- are still being subjected to the same voting procedure -- either in a state court, or a state legislature or a public referendum.

My feeling, for what it is worth, is that the bar should be raised from the present 50% so that perhaps a 75% majority would be needed before a group is denied a basic human right like marriage access.

Hopefully, Nate Silver will create new predictions for 2014 and
subsequent election days. We plan to add his predictions here.

References used:

The following information sources were used to prepare and update the above
essay. The hyperlinks are not necessarily still active today.